The present disclosure relates generally to medical devices and, more particularly, to sensors used for sensing physiological parameters of a patient.
This section is intended to introduce the reader to aspects of the art that may be related to various aspects of the present disclosure, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
In the field of medicine, doctors often desire to monitor certain physiological characteristics of their patients. Accordingly, a wide variety of devices have been developed for monitoring many such physiological characteristics. Such devices provide doctors and other healthcare personnel with the information they need to provide the best possible healthcare for their patients. As a result, such monitoring devices have become an indispensable part of modern medicine.
One technique for monitoring certain physiological characteristics of a patient is commonly referred to as pulse oximetry, and the devices built based upon pulse oximetry techniques are commonly referred to as pulse oximeters. Pulse oximetry is commonly used to measure blood-oxygen saturation of hemoglobin in arterial blood and/or the rate of blood pulsations corresponding to each heartbeat of a patient.
Pulse oximeters typically utilize a non-invasive sensor that transmits light through a patient's tissue and that photoelectrically detects the transmission of light through such tissue. One or more of the above physiological characteristics may then be calculated based upon the amount of light absorbed and/or scattered in the tissue. More specifically, the light passed through the tissue is typically selected to be of one or more wavelengths that may be absorbed and/or scattered by the blood in an amount correlative to the amount of the blood constituent present in the blood. The amount of light absorbed and/or scattered may then be used to estimate the amount of blood constituent in the tissue using various algorithms.
Pulse oximetry sensors may be applied to a patient's tissue site and secured, for example by adhesives, clips, or light pressure, to achieve a conforming fit. However, even if a sensor is relatively securely fitted to the tissue, physical motion of the patient may change the fit of the sensor and introduce artifacts into the measured signal. For example, for the case a bandage-type sensor wrapped around the fingertip, if the finger is bent at a first joint, parts of the sensor may fold or buckle away from the tissue. Such small changes in the conformation of the sensor may cause the optical components to lose their contact with the skin, resulting in changes to the emitted and/or detected light, which in turn may lead to signal artifacts. While these artifacts may sometimes be addressed by signal processing and filtering to mitigate the effects, such signal processing may be complex.